Naphthyl Copolyester\nwith High Glass Transition Temperatures:\nTunable Structure and Performance

A series\nof poly(ethylene bis[4-(2-hydroxyethoxy)phenyl]sulfone\n1,4-cyclohexanedimethylene 2,6-naphthalate) (PESCNs) copolyesters\nfrom amorphous to crystalline were prepared by melt polymerization.\nThe chemical structure and compositions were explored by hydrogen\nand carbon nuclear magnetic spectroscopy (<sup>1</sup>H NMR and <sup>13</sup>C NMR). The glass transition temperature (<i>T</i><sub>g</sub>) of copolyesters (128.1–134.5 °C) was higher\nthan that of PEN (about 120 °C) and showed tunable characteristics\nwith the composition of polymerization. With the incorporation of\nCHDM, the thermal stability of the copolyesters decreased slightly\nwhile the fluidity improved, owing to the easier conformational transition\nability of CHDM. An interesting transition from brittleness to toughness\nwas also achieved via regulating CHDM content. In addition, all the\nprepared copolyesters exhibited good transmittance (∼85%) under\nboth UV and C light sources. In view of these unusual performances,\nPESCNs exbibit potential for use in the fields of electronic devices,\nfibers, and cosmetic packaging.